#!/usr/bin/python3
# TODO: change the default file list to only apply to listing, not copying/erasing/creating/appending/zapping

VERSION = "0.1"

import os, sys, argparse

def file_copy(f,target,target_is_dir,force):
  print(f"call file_copy with args={target},{target_is_dir} and {force}")
  dest = target if not target_is_dir else target+'/'+os.path.basename(f)
  if os.path.exists(dest) and not force:
    go = input("The copy target <<" + dest + ">> exists. Overwrite? (y or n) ")
    if go != 'y' and go != 'Y':
      return
  print(f"copy from {f} to {dest}")

def file_zap(f,all_flag):
  print(f"zapping the comment history of {f}")
  if all_flag:
    print("zapping the entire database")

def file_erase(f, extra):
  print(f"erase the comment on file {f}")


def main(args):
  parser = argparse.ArgumentParser(description="Display or add comments to files",
    epilog="Some options conflict. Use only one of: -l -c -a -H -e -z -Z and one of -d -x")
  parser.add_argument('-V',"--version", action="version",version=f"dncli ver:{VERSION}")
  parser.add_argument('-v',"--verbose", action='store_true',help="verbose, almost debugging; do not use in scripts")
  parser.add_argument('-j',"--json",    action="store_true",help="output in JSON format")
  parser.add_argument('-l',"--listall", action="store_true",help="list all files, including those without comments")
  parser.add_argument('-d',"--db",      action="store_true",help="list comments from database")
  parser.add_argument('-x',"--xattr",   action="store_true",help="list comments from xattr")
  parser.add_argument('-n',"--minimal", action="store_true",help="output only comments; useful in scripting")
  parser.add_argument('-H',"--history", action="store_true",help="output the history of comments for a file")
  parser.add_argument('-c',"--create",  metavar="comment",  help="add a comment to a file")
  parser.add_argument('-a',"--append",  metavar="comment",  help="append to a comment on a file, separator=';'")
  parser.add_argument('-C',"--copy",    action="store_true",help="copy a file with its comments")
  parser.add_argument('-y',"--cp_force",action="store_true",help="copy over existing files")
  parser.add_argument('-e',"--erase",   action="store_true",help="erase the comment on a file")
  parser.add_argument('-z',"--zap",     action="store_true",help="clear the comment history on a file")
  parser.add_argument('-Z',"--zapall",   action="store_true",help="clear the comment history in the entire database")
  parser.add_argument('file_list',nargs='*',help="file(s) for comments; default is all files in ./")
  args = parser.parse_args()

  # default is to display all files that have comments

  # major modes are: display (-l -H), add-comment (-a -c -e), clear-history(-z -Z), copy (-C)
  # determine the major mode, then apply an appropriate function over the file_list

  #====== 1) build the file list =============

  files = args.file_list
  if not files:
    files = os.listdir(".")
  # if the user gave me a single dir...expand it
  elif len(files)==1 and os.path.isdir(files[0]):
    files = os.listdir(files[0])
  print("got the files:", files)

  #======= 2) build the function
  if args.create or args.append:
    print(f"create/append: {args.create} . {args.append}")
  elif args.erase:
    print(f"erase command")
    func = file_erase
    loop_args = (0,)
  elif args.zap or args.zapall:
    print(f"got a zap command {args.zap} . {args.zapall}")
    func = file_zap
    loop_args = (args.zapall,)
    if args.zapall:
      files = (1,)
  elif args.copy:
    print(f"got a copy command to {args.copy}")
    # the last item on the file list is the target
    n_files = len(files)
    if n_files < 2:
      print(f"the copy command requires at least two arguments, the last one is the destination")
      sys.exit(1)
    target = files[-1]
    target_is_directory = os.path.isdir(target)
    files = files[:-1]
    print(f"copy from {files} to {target}")
    if n_files > 2 and not target_is_directory:
      print(f"multiple copy files must go to a target directory")
      sys.exit(3)
    func = file_copy
    loop_args = (target, target_is_directory, args.cp_force)
  else:
    print(f"display command with option: {args.listall}")


  #====== 3) loop on the list, execute the function =============
  for f in files:
    func(f,*loop_args)


if __name__ == "__main__":
  main(sys.argv)